docs: def set_rendering_intent(self, rendering_intent):
          """Set rendering intent variant for sRGB chunk"""
          if rendering_intent not in (None,
                                      PERCEPTUAL,
                                      RELATIVE_COLORIMETRIC,
                                      SATURATION,
                                      ABSOLUTE_COLORIMETRIC):
              raise FormatError('Unknown redering intent')
          self.rendering_intent = rendering_intent